Modulation of aflatoxin B1 biotransformation in rabbit pulmonary and hepatic microsomes

In vitro cytochrome P450 monooxygenase and prostaglandin H-synthase mediated aflatoxin B1 biotransformation in guinea pig tissues: Effects of β-naphthoflavone treatment

“…The induction profile of AFB1 metabolites by BNF was similar to that obtained from BNF-treated mice (Raina et al 1985;Koser et al 1988) and rabbits (Daniels and Massey 1992). The data indicate that, unlike the P450 isozyme(s) catalyzing the epoxidation of AFB], BNF-inducible P450 isozymes of the P4501A class are responsible for the biotransformation of AFB1 to the less reactive metabolite, AFM 1.…”

“…For example, BNF treatment reduced AFB1-DNA binding and hepatocarcinogenesis in rats (Lotlikar 1989) and rainbow trout (Goeger et al 1988), and depressed mouse liver microsome-mediated AFB1 mutagenicity (Raina et al 1985). In addition, the pulmonary and hepatic production of AFMI, a non-toxic metabolite of AFB1, has been found to be induced by BNF treatment in mice (Raina et al 1985;Koser et al 1988) and rabbits (Daniels and Massey 1992). Therefore, BNF-treatment is generally considered to enhance detoxification of AFB t. However, experiments with hamsters have demonstrated that an AFBt-activating P450 isozyme can be greatly induced by BNF (Santhanam and Lotlikar 1989), suggesting the presence of species heterogeneity in the modification of AFB1 metabolism by PAH-type inducers.…”

A Review on Biological Control and Metabolism of Aflatoxin

“…They identified Yc 2 subunit of GST, which had high catalytic activity toward AFB 1 . Daniels and Massey (1992) investigated the role of polycyclic aromatic hydrocarbon-inducible forms of cytochrome-P 450 in the pulmonary and hepatic microsomal activation ( 3 [H] AFB 1 -DNA binding) and detoxification ( 3 [H] AFM 1 and 3 [H] AFQ 1 formation) of 3 [H] AFB 1 . They determined K m and V max of each reaction using different combinations of alpha and beta napthoflavone and in the presence or absence of NADPH-generating systems.…”

Aflatoxin B1-induced micronuclei and cell cycle alterations in lung and bone marrow cells and their modulation byPiper argyrophyllumextract

“…Human exposure occurs either by ingestion or inhalation of AFB 1 contaminated agricultural products [1]. In order to exert its biological effects, AFB 1 must be converted into its reactive epoxide, which is catalysed by the cytochrome P450-dependent mixed function oxygenase (MFO) system in liver [2] and extrahepatic tissues like lung [3].…”

“…The genotoxic effects of AFB 1 can be assessed by various methods, amongst which the micronucleus test is preferred for its ease and accuracy [5]. Micronuclei are cytoplasmic chromatin masses with the appearance of small nuclei that arise from broken chromosomal fragments under the action of clastogenic chemicals like AFB 1 . The micronucleus test is carried out on rapidly proliferating cells, most commonly the bone marrow cells.…”